枯草芽胞杆菌信号分子的分离纯化

为了获得较高纯度的B. subtilis分泌的信号分子,采用离子交换层析的方法对其进行分离纯化。本文研究了洗脱液及其pH和流速对分离纯化效果的影响,得到最佳层析条件：离子交换层析洗脱液(B液)为pH 4.0的NaAc + NaCl溶液,平衡液(A液)为pH 4.0的NaAc溶液,洗脱流速为2 mL/min；SDS-PAGE验证表明在5 kDa左右出现单个条带,且抑菌试验结果表明层析液中的B. subtilis信号分子能促进L. paracasei HD1.7产细菌素。

Separation and purification of the signal molecules of Bacillus subtilis

To obtain high- purity signal molecules secreted by B. subtilis and to explore the effect on the bacteriocin produced by L. paracasei HD1.7, the signal molecules were separated and purified by hollow fiber system and ion exchange chromatography in this study. SDS-PAGE was used to detect the purity and apparent molecular weight of signal molecules. The effect of signal molecules on L. paracasei HD1.7 bacteriocin was analyzed by antibacterial test. The results showed that three elution peaks occurred when pH 4.0 NaAc + NaCl solution was used as eluent, and the antimicrobial activity of L. paracasei HD1.7 added with elution peak P3 was higher than that of the original strain by 11.31%. However, the addition of elution peak P1 and P2 did not increase the antibacterial activity of L. paracasei HD1.7 compared with the original strain. Thus, P3 was the target elution peak containing the signal molecule, and the elution peak P3 was a single band detected by SDSPAGE. The optimal chromatographic condition was: ion exchange chromatography eluent (B eluent) was NaAc+ NaCl solution with pH 4.0, equilibrium eluent (A eluent) was NaAc solution with pH 4.0, the flow rate was 2 mL/min. SDS- PAGE analysis showed that a band appeared with molecule mass about 5 kDa. Subsequent antibacterial tests indicated that B. subtilis signal molecular in the chromatography solution could promote L. paracasei HD1.7 producing barteriocins.